A research project on the processing and characterization of cement-based composites containing high volume fraction of fibers is to be performed. The study concentrates on the manufacturing techniques and the constitutive laws based on the relationship among the fiber, matrix, interface, and the processing technique employed. The mechanical properties of these composites as a function of fiber lengths, interfacial properties, matrix properties, and the processing technique will be measured. Responses such as complete stress-strain curves, experimental R-curve, and post-peak stress-crack width relationship will be measured using digitally controlled closed loop tests. The in quantitative optical microscopy using image analysis techniques will be developed to measure stress induced microcracking. An R-Curve approach will be developed for the pull-out response of fibers. This approach will be implemented in a composite fracture model to predict the optimum material properties.
